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Left it "almost" assembled so you can see what to solder where.
Magic Number is 19 1/4 "
If you put your "polarity indicating" shrink tube over the outer "slide joint", You'll never have to remeasure, and your antennae will still 'retract' most of the way.

View attachment 15935
I built a fully integrated loop antenna crystal radio on a 23" diameter form (one slat of plastic/wood window blind). I like it because it is completely portable and does not require any additional antenna.

11 turns form the primary and 3 turns the secondary, small gauge phone line stranded copper, all close wound. All turns work out to about 1/2" wide. The primary currently measures 216 uH and I think the secondary was around 40 uH (I'll check this again as I think it was actually much lower, like 16 uH even).

I used a dual gang 15-400, 12-200 pF air variable capacitor. I tried connecting the 12-200 to either point A or B, or not at all. Point B gave about 2 uA more current in the secondary and Point A about 2 uA more again, so I left it at point A.

It tunes from a little over 600 kHz to a little over 1800 kHz. I'm able to pick up 10 stations and the antenna is highly directional, I can completely null the strongest...

My previous article on the topic of cheap vs. quality switching power supplies, I demonstrated the amount of hash generated in your HF rig with pictures from my panadapter display. After that article, I shelved the cheap Chinese supply and didn't look back. Unfortunately, the old power supply powering my D-Star UHF home repeater died, so I decided to put the cheap switching supply back in service. What a mistake.

The following panadapter screen captures show the amount of hash being generated by the cheap supply that is being picked up by my Elecraft K3 transceiver which is 4 feet away. In each pic, I powered on the supply and let the waterfall scroll a bit before taking the screen pic so you can see a some before-and-after.

The first pic is 75/80 meters, The arrow points out one of the frequencies where the hash is present:...

This just released from Connect Systems on their webpage and in the supporting Yahoo Group:
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CS7000
Multi Protocol Software Designed Radio
​

This radio is defined for the Amateur Market and will have an introductory price of $249. Capable of doing DMR, NXDN, dPMR, P25, ANALOG, D-STAR, AND FUSION Protocols. This radio is built to commercial strandards and will cover commercial frequencies and Amateur Frequencies. The first version will ship with Analog, DMR, and D-STAR protocols with future firmware updates allowing other protocols.

So you find an older XPS / Precision Workstation / Server on the curb. Grab it! Chances are the Power Supply still works. Here's the one I found. A BIG FAT one that attaches to the BOTTOM of a Dell Machine. 650 Watter. Pull it off, and salvage the wires inside the machine connected to "P3".
Almost any power supply will do... This one is rather nice. Remove Power! DUH. Remove Lid of PS. Cut wire ties (NOT the wires) that hold that snakehead mess of wires together so they are free.

YELLOW CIRCLE: On connector "P1" find the GREEN wire... pull ONE of the nearest BLACK wires and the green wire out of the connector, strip and solder/twist together. Cover with shrink tube for safety.

In an earlier thread about the various switching power supplies available on Amazon, there were questions posted about the difference between the authentic American made MegaWatt 30 amp supply and the cheaper Chinese imitation supply. I've purchased both supplies and used them extensively with my Elecraft K3 and can now report on the major difference.

First, here are links to the two supplies in question:

MegaWatt 30 amp switching power supply:

Chinese 30 amp switching power supply:

The two supplies look identical, although the Chinese supply does not include an AC power cord. However, the performance difference is significant: The MegaWatt has no "hash", while the Chinese unit has terrible "hash". I took pictures of the interference on the Panadapter that shows the difference visually.

The IC-2730 is Icom's newest dual band (2m/440Mhz) mobile radio which features dual wide RX, 50 watt power output, large display, lots of memories, and crossband repeat. The price-point of this radio (I paid $349) demonstrates the competitive market for rigs in this category. While the price of this radio is pretty aggressive, Icom is packaging this radio in a similar manner to the ID-5100: No brackets for the body or face.

The above picture does not show the power cord, manual, or mic hanger, but it does show you basically what is included in the package. The construction of the body is typical Icom quality: sleek but tough. The mic is the same as the one included with the ID-5100; reports of audio quality have been great and it's also easy to use to control the radio....

Well I must say it's been the most challenging and learning project yet to date for me.
I started this with a Heathkit SB-221 chassis.
You can see from the pics where I started, and now countless hours since my Christmas vacation. The project is working!
My homebrew KW+ 6 meter amplifier is born.
60 watts drive equals 1000w PEP on SSB.
She will key down legal limit with 100 watts drive!
Pair of 3-500z EIMAC tubes @ 3150 vdc at 750 mA plate current.

CK/Warren/Crusher/Shockwave...I still have and issue with output at full 100w drive. I am getting audio distortion. I am guessing my limited experience with VHF building, my coax routing or orientation is the cause.
HEY it's clean at 1000 watts, why sweet blood over 4-500 more!!!!

The new Icom IC-2730A dual band mobile with crossband repeat and optional bluetooth is now available for $370.

The rig features VHF/VHF, UHF/UHF dual simultaneous receivers as well as wideband receiver coverage. Adding bluetooth will cost you an additional $250 if you want to use the Icom bluetooth headset. Overall, this looks like a pretty nice radio.

VE7FMN, Fred sent me a Cooler KX Plus heatsink to try out for my Elecraft KX3, and I made a video of the simple install process. This heatsink really is made quite well; the finish and machining compliment the KX3 nicely. Here is the video of the installation procedure, plus a test at the end:

For a simple test, I ran the KX3 on 20 meters at 10 watts, FM mode into a dummy load until the rig gave a Hi Temp warning and folded the power back to 5 watts. With the stock heatsink, the Hi-Temp warning occurred after 8 minutes and 46 seconds. With the Cooler KX Plus, the keydown time extended to 27 minutes, 36 seconds until the warning. The starting PA temperature for both tests was 28 deg. Celsius and the rig folds the power back at just over 60 degrees.

It should be noted that the the higher you go in frequency with the KX3, the quicker it heats up. Adding an aftermarket heatsink allows you to operate at full power using high duty cycle modes,...

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